From: Daniel Axtens <dja@axtens.net>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: linuxppc-dev@ozlabs.org, mikey@neuling.org, sukadev@linux.vnet.ibm.com
Subject: Re: [PATCH V8 02/10] powerpc, perf: Restore privillege level filter support for BHRB
Date: Wed, 10 Jun 2015 13:43:57 +1000 [thread overview]
Message-ID: <1433907837.3096.11.camel@axtens.net> (raw)
In-Reply-To: <1433763511-5270-2-git-send-email-khandual@linux.vnet.ibm.com>
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In the subject line, privilege should only have 1 l, and I think it
should probably start with "powerpc/perf:" rather than "powerpc, perf:".
On Mon, 2015-06-08 at 17:08 +0530, Anshuman Khandual wrote:
> From: "khandual@linux.vnet.ibm.com" <khandual@linux.vnet.ibm.com>
>
> 'commit 9de5cb0f6df8 ("powerpc/perf: Add per-event excludes on Power8")'
Does this need a 'Fixes:' tag then?
> broke the PMU based BHRB privilege level filter. BHRB depends on the
> same MMCR0 bits for privilege level filter which was used to freeze all
> the PMCs as a group. Once we moved to individual event based privilege
> filters through MMCR2 register on POWER8, event associated privilege
> filters are no longer applicable to the BHRB captured branches.
>
> This patch solves the problem by restoring to the previous method of
> privilege level filters for the event in case BHRB based branch stack
> sampling is requested. This patch also changes 'check_excludes' for
> the same reason.
>
> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
> ---
> arch/powerpc/perf/core-book3s.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
> index c246e65..ae61629 100644
> --- a/arch/powerpc/perf/core-book3s.c
> +++ b/arch/powerpc/perf/core-book3s.c
> @@ -930,7 +930,7 @@ static int power_check_constraints(struct cpu_hw_events *cpuhw,
> * added events.
> */
Does this comment need to be updated?
> static int check_excludes(struct perf_event **ctrs, unsigned int cflags[],
> - int n_prev, int n_new)
> + int n_prev, int n_new, int bhrb_users)
> {
> int eu = 0, ek = 0, eh = 0;
> int i, n, first;
> @@ -941,7 +941,7 @@ static int check_excludes(struct perf_event **ctrs, unsigned int cflags[],
> * don't need to do any of this logic. NB. This assumes no PMU has both
> * per event exclude and limited PMCs.
> */
Likewise, does this comment need to be updated?
> - if (ppmu->flags & PPMU_ARCH_207S)
> + if ((ppmu->flags & PPMU_ARCH_207S) && !bhrb_users)
> return 0;
>
> n = n_prev + n_new;
> @@ -1259,7 +1259,7 @@ static void power_pmu_enable(struct pmu *pmu)
> goto out;
> }
>
> - if (!(ppmu->flags & PPMU_ARCH_207S)) {
> + if (!(ppmu->flags & PPMU_ARCH_207S) || cpuhw->bhrb_users)
You're using cpuhw->bhrb_users as a bool here, where it's an int. Could
you make the test more specific so that it's clear exactly what you're
expecting bhrb_users to contain?
> {
> /*
> * Add in MMCR0 freeze bits corresponding to the attr.exclude_*
> * bits for the first event. We have already checked that all
> @@ -1284,7 +1284,7 @@ static void power_pmu_enable(struct pmu *pmu)
> mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
> mtspr(SPRN_MMCR0, (cpuhw->mmcr[0] & ~(MMCR0_PMC1CE | MMCR0_PMCjCE))
> | MMCR0_FC);
> - if (ppmu->flags & PPMU_ARCH_207S)
> + if ((ppmu->flags & PPMU_ARCH_207S) && !cpuhw->bhrb_users)
> mtspr(SPRN_MMCR2, cpuhw->mmcr[3]);
>
> /*
> @@ -1436,7 +1436,8 @@ static int power_pmu_add(struct perf_event *event, int ef_flags)
> if (cpuhw->group_flag & PERF_EVENT_TXN)
> goto nocheck;
>
> - if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
> + if (check_excludes(cpuhw->event, cpuhw->flags,
> + n0, 1, cpuhw->bhrb_users))
> goto out;
> if (power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n0 + 1))
> goto out;
> @@ -1615,7 +1616,7 @@ static int power_pmu_commit_txn(struct pmu *pmu)
> return -EAGAIN;
> cpuhw = this_cpu_ptr(&cpu_hw_events);
> n = cpuhw->n_events;
> - if (check_excludes(cpuhw->event, cpuhw->flags, 0, n))
> + if (check_excludes(cpuhw->event, cpuhw->flags, 0, n, cpuhw->bhrb_users))
> return -EAGAIN;
> i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n);
> if (i < 0)
> @@ -1828,10 +1829,12 @@ static int power_pmu_event_init(struct perf_event *event)
> events[n] = ev;
> ctrs[n] = event;
> cflags[n] = flags;
> - if (check_excludes(ctrs, cflags, n, 1))
> + cpuhw = &get_cpu_var(cpu_hw_events);
Should this be using a this_cpu_ptr rather than a get_cpu_var? (as with
the power_pmu_commit_txn case?)
> + if (check_excludes(ctrs, cflags, n, 1, cpuhw->bhrb_users)) {
> + put_cpu_var(cpu_hw_events);
Likewise with this?
> return -EINVAL;
> + }
>
> - cpuhw = &get_cpu_var(cpu_hw_events);
> err = power_check_constraints(cpuhw, events, cflags, n + 1);
>
> if (has_branch_stack(event)) {
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next prev parent reply other threads:[~2015-06-10 3:45 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-08 11:38 [PATCH V8 01/10] powerpc, perf: Drop the branch sample when 'from' cannot be fetched Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 02/10] powerpc, perf: Restore privillege level filter support for BHRB Anshuman Khandual
2015-06-10 3:43 ` Daniel Axtens [this message]
2015-06-10 12:08 ` Anshuman Khandual
2015-06-11 3:28 ` Daniel Axtens
2015-06-12 7:06 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 03/10] powerpc, perf: Re organize BHRB processing Anshuman Khandual
2015-06-10 4:36 ` Daniel Axtens
2015-06-10 12:09 ` Anshuman Khandual
2015-06-11 3:32 ` Daniel Axtens
2015-06-12 7:05 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 04/10] powerpc, perf: Re organize PMU based branch filter processing in POWER8 Anshuman Khandual
2015-06-10 5:07 ` Daniel Axtens
2015-06-10 12:09 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 05/10] powerpc, perf: Change the name of HW PMU branch filter tracking variable Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 06/10] powerpc, lib: Add new branch analysis support functions Anshuman Khandual
2015-06-10 5:33 ` Daniel Axtens
2015-06-10 12:10 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 07/10] powerpc, perf: Enable SW filtering in branch stack sampling framework Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 08/10] powerpc, perf: Change POWER8 PMU configuration to work with SW filters Anshuman Khandual
2015-06-10 5:49 ` Daniel Axtens
2015-06-10 12:10 ` Anshuman Khandual
2015-06-11 3:38 ` Daniel Axtens
2015-06-08 11:38 ` [PATCH V8 09/10] powerpc, perf: Enable privilege mode SW branch filters Anshuman Khandual
2015-06-11 1:19 ` Daniel Axtens
2015-06-12 7:04 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 10/10] selftests, powerpc: Add test for BHRB branch filters (HW & SW) Anshuman Khandual
2015-06-09 5:41 ` Anshuman Khandual
2015-06-11 2:09 ` Daniel Axtens
2015-06-12 7:02 ` Anshuman Khandual
2015-06-12 7:26 ` Madhavan Srinivasan
2015-06-12 8:59 ` Anshuman Khandual
2015-06-10 3:21 ` [PATCH V8 01/10] powerpc, perf: Drop the branch sample when 'from' cannot be fetched Daniel Axtens
2015-06-10 12:02 ` Anshuman Khandual
2015-06-11 2:22 ` Daniel Axtens
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